Investigating the antibacterial effect of extracts of Malva sylvestris and Elettaria cardamom plants compared to chlorhexidine on Streptococcus mutans bacteria and Investigating their synergistic effect in laboratory conditions

Abstract

Introduction Plant extracts are the best candidates for inhibiting antibiotic-resistant infectious bacteria. In this study, we investigated the antibacterial effect of Malva sylvestris and Elettaria Cardamom plant extracts compared to 0.2% chlorhexidine on Streptococcus mutans bacteria and investigated their synergistic effect. Materials and methods Malva sylvestris plant extract and Elettaria Cardamom seeds were prepared using maceration method. In order to standardize Streptococcus mutans bacteria, a suspension with a standard equal to 0.5 McFarland was prepared from bacteria multiplied in blood agar culture medium. The investigation of antimicrobial properties was done using the diameter of the halo of non-growth and the concentrations of MIC and MBC. To determine the MIC value of cheese plant extract and green cardamom seeds, the serial dilution method was used in a 96-well microplate and then the microbial suspension was inoculated into the wells. . To determine the MBC value of plant extracts, microbial re-cultivation was performed from the contents of the house corresponding to the MIC and two houses with a higher concentration. The results of the tests were performed in the form of statistical indices and Kruskal-Wallis and Mann-Whitney tests using SPSS24 software. Results According to the results of the halo diameter of non-growth, the antimicrobial property of chlorhexidine was significantly higher than the extracts of Malva sylvestris, Elettaria Cardamom and the combination of the two extracts. Increasing the concentration of the extracts increased the antibacterial properties. In the concentrations of 25, 50 and 100% of the extracts, the antibacterial properties of the three groups were significantly different, and in all three concentrations, the antibacterial property of Malva sylvestris was significantly lower than that of cardamom. In concentrations of 12.5% and 6.25% of the extracts, there was no significant difference in the antibacterial properties of the three extracts. MIC concentration was also similar in Malva sylvestris (225) and cardamom (200) extracts, but MBC concentration in cardamom extract (200) was lower than Malva sylvestris extract (450). No synergistic property was observed in the combination of two extracts in any of the studied concentrations. Conclusion Malva sylvestris and Elettaria cardamom plant extracts had less antimicrobial properties than chlorhexidine and synergistic properties were not observed in the combination of the extracts of these two plants